Detecting Malicious Network Content Using Virtual Environment Components

ABSTRACT

Malicious network content is identified based on the behavior of one or more virtual environment components which process network content in a virtual environment. Network content can be monitored and analyzed using a set of heuristics. The heuristics identify suspicious network content communicated over a network. The suspicious network content can further be analyzed in a virtual environment that includes one or more virtual environment components. Each virtual environment component is configured to mimic live environment components, for example a browser application component or an operating system component. The suspicious network content is replayed in the virtual environment using one or more of the virtual environment components. The virtual environment component behavior is analyzed in view of an expected behavior to identify malicious network content. The malicious network content is then identified and processed.

BACKGROUND

Presently, malicious network content (e.g., malicious software or malware) can attack various devices via a communication network. For example, malware may include any program or file that is harmful to a computer user, such as bots, computer viruses, worms, Trojan horses, adware, spyware, or any programming that gathers information about a computer user or otherwise operates without permission.

Adware is a program configured to direct advertisements to a computer or a particular user. In one example, adware identifies the computer and /or the user to various websites visited by a browser on the computer. The website may then use the adware to either generate pop-up advertisements or otherwise direct specific advertisements to the user's browser. Spyware is a program configured to collect information regarding the user, the computer, and/or a user's network habits. In an example, spyware may collect information regarding the names and types of websites that the user browses and then transmit the information to another computer. Adware and spyware are often added to the user's computer after the user browses to a website that hosts the adware and/or spyware. The user is often unaware that these programs have been added and are similarly unaware of the adware and/or spyware's function.

Various processes and devices have been employed to prevent the problems that malicious network content can cause. For example, computers often include antivirus scanning software that scans a particular client device for viruses. Computers may also include spyware and/or adware scanning software. The scanning may be performed manually or based on a schedule specified by a user associated with the particular computer, a system administrator, and so forth. Unfortunately, by the time a virus or spyware is detected by the scanning software, some damage on the particular computer or loss of privacy may have already occurred. Additionally, it can take weeks or months for new Anti-Virus signatures to be manually created and for an anti-virus application to be updated. Moreover, polymorphic exploits are also an issue that limits the effectiveness of some anti-virus applications.

In some instances, malicious network content comprises a bot. A bot is a software robot configured to remotely control all or a portion of a digital device (e.g., a computer) without authorization by the digital device's legitimate owner. Bot related activities include bot propagation and attacking other computers on a network. Bots commonly propagate by scanning nodes (e.g., computers or other digital devices) available on a network to search for a vulnerable target. When a vulnerable computer is scanned, the bot may install a copy of itself. Once installed, the new bot may continue to seek other computers on a network to infect. A bot may also be propagated by a malicious web site configured to exploit vulnerable computers that visit its web pages.

A bot may also, without the authority of the infected computer user, establish a command and control communication channel to receive instructions. Bots may receive command and control communication from a centralized bot server or another infected computer (e.g., via a peer-to-peer (P2P) network established by a bot on the infected computer). When a plurality of bots (i.e., a bot net) act together, the infected computers (i.e., zombies) can perform organized attacks against one or more computers on a network, or engage in criminal enterprises. In one example, bot infected computers may be directed to flood another computer on a network with excessive traffic in a denial-of-service attack. In another example, upon receiving instructions, one or more bots may direct the infected computer to transmit spam across a network. In a third example, bots may host illegal businesses such as pharmaceutical websites that sell pharmaceuticals without a prescription.

Malicious network content may be distributed over a network via web sites, e.g., servers operating on a network according to an HTTP standard. Malicious network content distributed in this manner may be actively downloaded and installed on a user's computer, without the approval or knowledge of the user, simply by accessing the web site hosting the malicious network content. The web site hosting the malicious network content may be referred to as a malicious web site. The malicious network content may be embedded within data associated with web pages hosted by the malicious web site. For example, a web page may include JavaScript code, and malicious network content may be embedded within the JavaScript code. In this example, the malicious network content embedded within the JavaScript code may be obfuscated such that it is not apparent until the JavaScript code is executed that the JavaScript code contains malicious network content. Therefore, the malicious network content may attack or infect a user's computer before detection by antivirus software, firewalls, intrusion detection systems, or the like.

SUMMARY

The behavior of one or more virtual environment components which process network content in a virtual environment is used to identify malicious network content. Network content can be monitored and analyzed using a set of heuristics. The heuristics identify suspicious network content communicated over a network. The suspicious network content can further be analyzed in a virtual environment that includes one or more virtual environment components. Each virtual environment component is configured to mimic live environment components, for example a browser application component or an operating system component. The suspicious network content is replayed in the virtual environment using one or more of the virtual environment components. The virtual environment component behavior is analyzed in view of an expected behavior. Malicious network content is detected based on observed component behavior that deviates from an expected behavior. The malicious network content is then identified and processed.

An embodiment detects malicious network content by receiving network content detected to be suspicious. A virtual environment component within a virtual environment is then configured to mimic a real application. The real application is configured to process the suspicious network content. The suspicious network content is then processed by the virtual environment component within a virtual environment. Suspicious network content can be identified as malicious network content based on a behavior for the virtual environment component. A computer readable storage medium can contain instructions executable by a processor for detecting malicious network content.

An embodiment processes network content by receiving suspicious network content. The suspicious network content is detected within a copy of network content communicated over a network. An agent is then configured to monitor processing of the suspicious network content within a virtual environment. At least one virtual environment component is configured to process the suspicious network content within the virtual environment. An agent can detect an anomaly associated with the virtual environment component. A signature is then generated from the suspicious network content to apply to subsequent network content.

An embodiment may include a system including a first module, a pool of virtual environment components, a scheduler and a replayer. The first module can access suspicious network content. The scheduler can retrieve a virtual environment component from the virtual environment pool. The virtual environment component can be configured to mimic a real application. The replayer processes the suspicious network content using the retrieved virtual environment component within a virtual environment.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is a block diagram of an exemplary malicious network content detection environment.

FIG. 2 is a block diagram of an exemplary virtual environment component pool.

FIG. 3 is a block diagram of an exemplary virtual environment.

FIG. 4 is a flow chart of an exemplary method for detecting and processing malicious network content.

FIG. 5 is a flow chart of an exemplary method for configuring virtual environment components.

FIG. 6 is a flow chart of an exemplary method for replaying suspicious network content.

FIG. 7 is a flow chart of an exemplary method for detecting malicious network content.

FIG. 8 is a flow chart of an exemplary method for identifying and processing malicious network content.

FIG. 9 is a block diagram of an exemplary malicious network content detection device.

DETAILED DESCRIPTION

The present technology utilizes one or more virtual environment components to analyze network content in a virtual environment. Network content can be monitored and analyzed using a set of heuristics. The heuristics can identify suspicious network content communicated over a network between two or more computing devices. The suspicious network content can further be analyzed in a virtual environment. The virtual environment may include one or more virtual environment components configured to mimic live environment components. The virtual environment components may include, for example, an application component such as a browser application component, an operating system component, a network component or some other component. The suspicious network content is replayed in the virtual environment using one or more of the virtual environment components. The virtual environment components can then be analyzed in view of their expected behavior. Malicious network content can be detected based on observed component behavior that deviates from an expected behavior. The malicious network content can then be identified and processed.

In some embodiments, a virtual environment component may be configured as a browser application. The virtual environment browser application can be configured to mimic a real browser application configured to receive and transmit network content being monitored. For example, a virtual environment browser application can be configured with software plug-ins, add-ons, preferences, proxy information, and settings associated with a real browser application that communicates over a network. The behavior of the virtual environment browser application is monitored while it is processing suspicious network content. When the actual or observed behavior of the virtual environment browser application differs from an expected behavior for the browser application, the suspicious network content processed by the virtual environment browser application can be designated as malicious network content. For example, when suspicious network content downloaded to a virtual environment browser application initiates a request to a remote server without using a designated browser application proxy, the network content can be designated as malicious.

In some embodiments, a virtual environment component may be configured as an operating system of a computer. The virtual environment operating system may be configured to mimic the appearance and performance of an operating system of a computer that processes network traffic. The virtual environment operating system can be monitored during processing of suspicious network content to determine if settings or parameters are improperly changed or the virtual environment operating system does not behave as expected. If the observed behavior does not match the expected behavior, the network content processed by the virtual environment operating system is identified as malicious network content. Furthermore, if a setting, parameter, or other aspect of the virtual environment operating system is changed (or attempted to be changed) improperly, the current detection system may immediately generate a signature and apply the signature against future network content. In some embodiments, a virtual environment component can include an agent that monitors and/or observes changes to a virtual operating system component. Details of virtual environment components are discussed in more detail below.

FIG. 1 is a block diagram of an exemplary malicious network content detection environment. The environment of FIG. 1 includes server 105 and client 110 communicating over network 120. Network tap 115 is also in communication with network 120 and may intercept communications sent over network 120, for example the communications between client 110 and server 105. Network tap 115 can generate a copy of the intercepted communications and provide the copied communications to malicious network content detection system 125.

Network 120 may be implemented as the Internet or other WAN, a LAN, intranet, extranet, private network, public network, combination of these, or other network or networks.

Server 105 provides a network service over network 120. In some embodiments when network 120 is implemented as the Internet, server 105 can provide a web service. Server 105 may include one or more applications 107 and operating system 109. In some embodiments, application 107 is a web application providing a web service over network 120. Operating system 109 may be an operating system suitable for use by a server, such as WINDOWS, LINUX, or NOVEL NETWARE operating system.

Client 110 may execute one or more applications 112 on operating system 114. In some embodiments, one or more applications on client 110 may utilize a service provided by server 105 over network 120. In some embodiments, client 110 may utilize a web service provided over network 120 by server 105. Application 112 may be any of several types of applications, such as a browser application, instant messaging application, e-mail application, an other application which can communicate over network 120 or is affected by network content communicated to or from client 110 over network 120. Operating system 114 may be any operating system suitable for a client 110, such as WINDOWS, UNIX, or other operating system.

Malicious network content detection system 125 includes heuristic module 130, heuristics database 135, scheduler 140, virtual environment component pool 145 and virtual environments 150. The system 125 receives a copy of network content from network tap 115. The network content may include, for example, network data. The network content is then provided to heuristic module 130 which applies heuristics to received network data. Heuristics module 130 may access the heuristics from heuristics database 135. When application of the heuristics indicates that one or more data packets of the network data have a suspicious characteristic or are otherwise suspicious, heuristic module 130 may provide the suspicious data packets to scheduler 140. In some embodiments, suspicious data packets include data packets that might contain malicious network content. Examples of malicious network content include a worm, virus, trojan horse or other malicious code. Scheduler 140 receives suspicious network content from heuristic module 130 and replays the suspicious network content in virtual environment 150. In some embodiments, “replay” of the suspicious network content includes processing the suspicious network content in a virtual environment 150 that is configured to mimic the real environment in which the network content was or was intended to be processed. Configuring the replay of suspicious network content can include retrieving one or more virtual environment components from virtual environment component pool 145, configuring the virtual components, providing the virtual components to virtual environment 150, and executing playback of the suspicious network data.

Virtual environment component pool 145 contains a pool of different component types, such as applications, operating systems, and other components. Virtual environment component pool 145 is discussed in more detail below with respect to FIG. 3. Virtual environment 150 is used to replay suspicious network content using one or more components. Virtual environment 150 is discussed in more detail below with respect to FIG. 2. The operation of exemplary embodiments of a heuristic module, heuristics database, and scheduler are discussed in more detail in U.S. patent application Ser. No. 12/263,971, filed on Nov. 3, 2008, titled, “Systems and Methods for Detecting Malicious Network Content”, which is incorporated by reference herein in its entirety.

FIG. 2 is a block diagram of an exemplary virtual environment component pool. In some embodiments, the virtual environment component pool of FIG. 2 provides more detail for virtual environment component pool 145 illustrated in FIG. 1. Virtual environment component pool 145 includes virtual environment applications 205, virtual environment operating systems 210, virtual environment networks 215, and virtual environment agents 220.

Each of virtual environment applications 205 may be configured to appear and perform as a real application which processes or is affected by network data. Examples of virtual environment applications 205 include a browser application, such as “Internet Explorer” by Microsoft Corporation or “FireFox” by Mozilla, instant messaging application, client e-mail application, other applications that process data communicated over a network, and other applications. The virtual environment applications may be implemented as one or more templates of a type of application, or a specific instance of a particular application. The virtual environment applications can be retrieved, configured and used within one or more virtual environments 150. The behavior of the virtual environment applications can be monitored and compared to an expected behavior to determine whether or not any variances exist which may indicate malicious network content and/or data.

Virtual environment operating system 210 can be implemented to appear and perform as any of several widely known operating systems for computers which process network data, for example WINDOWS, UNIX, or other operating systems. The virtual environment operating system may be configured to mimic a real operating system and monitor to detect attempted changes and actual changes to the operating system which are unexpected.

Virtual environment agent 220 can detect changes in a virtual environment component, such as a virtual environment application or virtual environment operating system. In some embodiments, a virtual environment agent 220 may detect changes to a virtual environment component that are not made using a standard process, changes to virtual environment component settings that should not be changed, and other changes to a virtual environment component. For example, the virtual environment agent 200 may detect when a change is made to an operating system setting using a non-standard process.

Virtual environment network 215 may be implemented to include a virtual switch, an intranet, the Internet, or some other network. The virtual environment network 215 is configured with protocols that mimic the real network in which the network data is communicated.

FIG. 3 is a block diagram of an exemplary virtual environment. In some embodiments, the exemplary virtual environment of FIG. 3 provides more detail of virtual environment 150 of FIG. 1. Virtual environment 150 includes replayer 305, virtual environment network 310, virtual environment operating system 315, virtual environment applications 320-325, and virtual environment agent 330.

Replayer 305 replays network content in the virtual environment network 310 by receiving and transmitting communications with virtual environment operating system 315 over virtual environment network 310. The communications can be processed by virtual environment operating system 315 as well as by one or more virtual environment applications 320-325. In some embodiments, suspicious network data is processed by operating system 315 and virtual environment applications 320 and/or 325. Virtual environment network 310 may receive suspicious network data from replayer 305 and provide the suspicious network data to virtual environment operating system 315. Virtual operating system 315 may process the suspicious network content and optionally provide the suspicious network content to a virtual environment application. In some embodiments, virtual operating system 315 is configured to mimic a server or server applications, such as server 105, application 107 or operating system 109. Processing suspicious network content in a virtual environment is discussed in more detail below with respect to the method of FIG. 4.

Virtual environment network 310 may be retrieved from virtual environment component pool 145. The virtual environment network 310 may be implemented to include a switch or a gateway, or some other software implementation of a network which mimics an actual communications network. In some embodiments, the virtual environment network 310 may process and implement the transmission of data in a manner that simulates the processing and transmission of data by an actual network. In some embodiments, the communications processed through virtual environment network 310 are monitored. In some embodiments, implementing a virtual environment network 310 is optional, in which case replayer 305 communicates with virtual environment operating system 315 directly.

Virtual environment operating system 315 is configured to mimic (e.g., appear and perform in a similar manner) a real operating system, for example an operating system 114 for client 110 that processes data over network 120. In some embodiments, virtual environment operating system 315 is implemented as code that emulates an operating system and can interact with one or more virtual environment applications as an actual operating system would. In some embodiments, the virtual environment operating system is implemented as an actual operating system executing within a virtual environment.

Virtual environment operating system 315 may communicate data between virtual environment network 210 (or replayer 305) and one or more virtual environment applications. For example, virtual environment operating system 315 may receive requests from a virtual environment application, route the request to replayer 305, and route response data, for example suspicious network content data, from replayer 305 to virtual environment application 220 or 225, respectively. In some embodiments, communications, settings and other parameters aspects of the behavior of virtual environment operating system 315 within virtual environment 150 are monitored. In some embodiments, virtual environment operating system 315 is optional.

Virtual environment applications 320 and 325 are each configured to behave as an application that processes or is affected by network content on a client computer or server. For example, a virtual environment application may be implemented as code that emulates a real application to mimic the behavior of the real application, for example the behavior of application 112 on client 110. In some embodiments, a virtual environment application may be implemented as a copy of the actual application which is executed within the virtual environment.

Virtual environment applications can be configured and controlled to replicate the processing of suspicious content data. For example, when replaying suspicious content data, the virtual environment application can be controlled to submit a request for data over a virtual network. At least a portion of the suspicious content data is transmitted to the virtual environment application in response to the request. Replay of suspicious network data continues until the content data has been replayed in its entirety. The communications, settings and other aspects of the behavior of virtual environment applications within virtual environment 150 can be monitored.

One or more virtual environment agents 330 can be configured to monitor the behavior and/or state of one or more virtual environment components. In some embodiments, virtual environment component behavior can include requests for data, sending or receiving data over a network, processing and/or storing data, or other operations performed the component. In some embodiments, the virtual environment component state may include a “snapshot” of the virtual environment parameters and settings, for example values for components settings, status of a portion component portion (i.e., error conditions, interrupts, availability of a buffer), or values for settings or parameters for the component. For example, a virtual environment agent can monitor changes made to a virtual environment operating system 315. In some embodiments, if a setting is changed to an improper value or an improper procedure is used to change a setting to the operating system, the agent can detect the code associated with suspicious network content which performed the change.

In addition to the network, operating system, application, and agent components illustrated in virtual environment 150, other types of virtual environment components can be used within virtual environment 150 to process suspicious network data. For example, a virtual environment 150 may include virtual environment hardware to mimic a hardware protocol, ports, or other behavior of an actual hardware machine.

The exemplary methods of FIGS. 4-8 relate to detecting and processing malicious network content. Throughout the following discussion of FIGS. 4-8, examples are occasionally discussed which relate to virtual environment components comprising a browser application and an operating system. These exemplary references are for purposes of discussion only and are not intended to limit the scope of the present technology.

FIG. 4 is a flow chart of an exemplary method for detecting and processing malicious network content. The method of FIG. 4 begins with intercepting network content at step 405. Network tap 115 intercepts network content sent over network 120 between server 105 and client 110. After intercepting network content, suspicious network content is identified at step 410. Suspicious network content can be detected by heuristic module 130 as module 130 applies heuristics to network content provided by network tap 115. For example, if a heuristic applied by heuristic module 130 identifies a suspicious characteristic in the network content, then the network content is considered suspicious. Exemplary methods for detecting suspicious network content using heuristics and other methods are disclosed in U.S. patent application Ser. No. 12/263,971, filed on Nov. 3, 2008, titled, “Systems and Methods for Detecting Malicious Network Content”, which is incorporated by reference herein in its entirety.

Virtual environment components and agents can be configured at step 415. Once identified, suspicious network data can be processed in a virtual environment by virtual environment components to determine if the suspicious content should be identified as malicious. In some embodiments, one or more virtual environment agents may be used to monitor the state or behavior of the virtual environment components. Scheduler 140 may configure virtual environment components by retrieving components from virtual environment component pool 145 and configuring the retrieved components to mimic real applications and other software. The agents can be configured to monitor the configured components. Configuring virtual environment components and agents is discussed in more detail below with respect to FIG. 5.

Suspicious network content is accessed at step 420. The suspicious network content includes the content identified at step 410 and may include data packets containing suspicious characteristics as well as related data packets. For example, suspicious network content may include data packets comprising the request which resulted in a response having a suspicious characteristic as well as additional data retrieved by the code containing the suspicious characteristic.

Suspicious network content is replayed using the virtual environment components at step 425. The suspicious network content is replayed within virtual environment 150 by replayer 305. In some embodiments, replaying virtual network content includes processing the suspicious network data by one or more virtual environment components within virtual environment 150. For example with respect to web page content having suspicious content, replayer 305 transmits the suspicious network content containing the suspicious characteristic to be processed by a virtual environment operating system and virtual environment browser application. The actual network content copied at step 405 is provided to the one or more of the virtual environment components illustrated in FIG. 3. More detail for replaying suspicious network content is discussed below with respect to the method of FIG. 6.

After replaying the suspicious network content, the virtual environment components are analyzed to detect malicious network content at step 430. In some embodiments, each virtual environment component is associated with an expected behavior. The expected behavior for a component is compared to the behavior observed for the virtual environment component as the component processed the suspicious network content. If there was a difference between the observed behavior and the expected behavior, the suspicious network content is determined to be malicious network content. More detail for detecting malicious network content by analyzing virtual environment component behavior is discussed in more detail below with respect to the method of FIG. 7.

After detecting malicious network content, the malicious network content is identified and processed at step 435. In some embodiments, an identifier is created for the malicious network content and further processing is performed to minimize damage resulting from the malicious network content. The further processing may include blocking subsequent network data that resembles the identified malicious network content, removing the malicious network content from one or more clients within a computer network, and other processing. Identifying and processing malicious network content is discussed in more detail below with respect to FIG. 8.

FIG. 5 is a flow chart of an exemplary method for configuring virtual environment components. In some embodiments, the method of FIG. 5 provides more detail for step 415 of the method of FIG. 4. First, components in a live environment are identified at step 505. The components may be identified on client 110, server 105, or some other machine (real or virtual) or environment that processes or is affected by network data communicated over network 120. The identification can be performed by scheduler 140 based on information in network data, a reporting server with information for one or more computers exposed to the network content (e.g., computers that transmit or receive the suspicious content), data stored locally on malicious network content detection system 125, or from some other source. Examples of real environment components include a browser application, electronic messaging client, instant messaging client, an operating system, or some other software or hardware on a machine that accesses network content.

Each of steps 510-530 can be performed by scheduler 140 within system 125. Virtual environment components are retrieved for the identified real environment components at step 510. The virtual environment component can be associated with types of applications, operating systems, or other code that can be executed in a real environment. The components can be retrieved by scheduler 140 from virtual environment component pool 145.

The one or more virtual environment components may be configured to mimic a real environment application at step 515. Scheduler 140 can configure the component to mimic the appearance and behavior of the real environment application. The configuration can be such that any suspicious code will not be able to detect a difference between the real component and the virtual environment component application. For example, a virtual environment network application 320 can be configured as Microsoft's “Internet Explorer” or Mozilla's “Firefox” browser application, wherein the component is configured with protocols, user preferences, proxy addresses, encryption preferences, add-in code, and other settings that can correspond to an actual browser application executing on client 110.

In some embodiments, rather than execute code that mimics the application, a copy of the actual application is executed within the virtual environment. Thus, the application is executed within a virtual operating system, configured with settings and parameters associated with a real application.

Virtual environment components can be configured to mimic a real environment operating system at step 520. The virtual environment operating system may be configured to mimic an operating system used to process network data communicated over network 120 by server 104 or client 110. For example, the component can be configured to mimic Microsoft's “Windows” operating system. The configuration may include setting a number of port addresses, settings, and other data.

Virtual environment components may then be configured to mimic the real environment network at step 525. Configuring a virtual environment component network may involve setting up protocols, and other features to mimic network 120. In some embodiments, the network may be configured as a virtual switch, relay station, or some other network system for relaying content data. The method of FIG. 5 then ends.

Virtual environment agents are retrieved and configured at step 530. A virtual environment agent can be implemented as code which monitors component behavior and settings in a virtual environment. The virtual environment agents may detect behaviors and changed settings as they occur and may detect whether the behaviors or setting changes are expected or unexpected. If unexpected, the suspicious network content which implemented or caused the change is identified as malicious. Identifying malicious code is discussed in more detail below.

In some embodiments, a virtual machine hardware component may be configured as well. In this case, the virtual machine hardware may be configured to mimic real hardware ports, settings, and other aspects of the actual hardware used to implement an operating system and application components.

FIG. 6 is a flow chart of an exemplary method for replaying suspicious network content. In some embodiments, the method of FIG. 6 provides more detail for step 425 of the method of FIG. 4. The discussion of the method of FIG. 6 will refer to an example regarding replaying network content using a browser application.

An initial request is replayed from a virtual environment application to a virtual environment operating system at step 605. In some embodiments, the initial request is configured based on network content (for example, consisting of network data packets) copied by network tap 115. For example, network content may be stored for period of time. When one or more network content data packets are determined to be suspicious, all network content associated with the suspicious data packets are retrieved and replayed. For example, network content provided to a network browser application in response to a request may contain suspicious data packets. Once data packets in the response are determined to be suspicious, the request which generated the response as well as other communications occurring after the response was received all retrieved in their entirety.

In some embodiments, the initial request is configured by replayer 305 or scheduler 140 and sent from the virtual environment application 320 to the replayer 305. Transmission of the initial request can result in virtual environment application behavior corresponding to the request. For example, for a network browser application, the request may initiate creating of a cookie associated with the request. The cookie can include a timestamp for and an identifier associated with the request, as well as creation of other data.

Suspicious network content is provided to a requesting virtual environment application at step 610. In response to the initial request in step 605, the network content is transmitted to the virtual environment application to replicate transmission of the network content to the requesting client in a real computing environment. For example, in reply to an HTTP request, the response may include HTTP packets, image data packets, and other content comprising a response to the request. The data packets comprising the response are transmitted to virtual operating system 315 by replayer 305 over virtual environment network 310. Virtual operating system 315 receives the content data, optionally processes the data, determines which virtual environment application that will receive the data, and “transmits” the content data to the virtual environment application. For a virtual network browser application, the content data is transmitted to the browser application to be loaded as a web page or other content.

In some embodiments, the network content is not provided to a virtual environment operating system, but rather directly to the virtual environment application.

The suspicious network content is then processed by the virtual environment application at step 615. For example, a virtual environment browser application may load web page data and image data, execute a script, or provide flash video as included in the response data packets.

When the received network content contains code that is malicious (although it may not yet be identified as malicious before it is executed), the content is processed by the virtual environment application just as it would be when the network content and malicious code would be executed by a real application. For example, malicious content may consist of code consisting of an executable. When executed by the virtual environment browser application, the executable code may attempt to transmit a message to a server, retrieve data within the local environment, change a setting in the virtual environment browser application, or perform some other operation.

While processing the suspicious network content, the virtual environment application, operating system, network and other virtual environment components are monitored by one or more virtual environment agents 330 at step 620. As suspicious network data is “replayed” by processing the network data by the virtual environment components, the behavior of each component can be detected, logged, stored, reported and/or otherwise monitored by an agent. One agent may monitor a single component or multiple components.

For example, a virtual environment agent may detect behavior in a virtual environment browser application. When the virtual environment browser receives and processes suspicious content data, the browser application may execute executable code within the data. The executable code may attempt to transmit a message over the virtual network (i.e., to replayer 305) improperly. For example, the executable may attempt to send a message directly to a server instead of using a proxy address specified by the virtual environment browser application. A virtual environment agent monitoring the browser application may detect all requests sent by the virtual browser application, and thereby detect the improper request which did not go to the proxy address.

A virtual environment agent may also detect changes to an operating system which are improper. For example, when executed by a virtual environment application, an executable or other code in received network content may change or attempt to change an operating system setting, value, or otherwise change the virtual environment operating system. The virtual environment agent may detect the change or attempted change by intercepting or monitoring all changes to the virtual environment operating system. As another example, the operating system may receive data to be stored. The data may comprise an executable, which may attempt to access information, control an application, or perform some other function. When data received by the operating system for storage is an executable or other executable code, the execution of the data is monitored by the agent to determine the effects of the data execution.

When monitoring data, a virtual environment agent may record information regarding the effects and identification of the suspicious network data when the data is being processed in the virtual environment. For example, the virtual environment agent may identify application and operating system settings and values affected by the suspicious network content, values before and after they are affected during processing of the suspicious network content, changes to processes such as an operating system “start-up” process, and other changes. The virtual environment agent may also identify a request made by the suspicious network content, including requests to transmit data over a network, requests for local data access, and other requests. This and other data may be stored and/or reported by the virtual environment agent for later processing.

FIG. 7 is a flow chart of an exemplary method for detecting malicious network content. In some embodiments, the method of FIG. 7 provides more detail for step 430 of the method of FIG. 4 and is performed by scheduler 140. First, expected behavior for a virtual environment component such as an application, operating system and/or network is accessed at step 705. The expected behavior data can be determined from stored behavior patterns associated with each component. The behavior patterns may be accessed locally or remotely by scheduler 140. For example, a stored behavior pattern for a virtual environment network browser can indicate that all requests to transmit over a network should be directed towards a proxy address specified by the virtual environment network browser. A stored behavior pattern for an operating system can indicate parameter values that should not be changed as well as code that should be invoked when attempting to change a particular parameter.

The actual behavior pattern of the virtual environment application or operating system is then compared with the expected behavior pattern for the application or operating system at step 710. The actual behavior may be retrieved from data stored by one or more virtual environment agents 330. For example, the expected behavior for transmitting a request by a virtual environment network browser can include sending a content request to a proxy address set within the network browser settings. The actual behavior may include a content request initiated by executable code in the suspicious network content that attempts to transmit a network request directly.

If a difference is detected between the actual behavior and expected behavior at step 715, the suspicious network content is identified and processed as malicious network content at step 720. Identifying and processing malicious network content is discussed in more detail below with respect to FIG. 8. After identifying and processing the malicious network content, the method of FIG. 7 continues to step 725. In some embodiments, the suspicious network data is flagged to be identified and processed later and the operation of the method of FIG. 7 continues to step 725.

If no difference is detected between the actual behavior and expected behavior at step 715, the actual behavior for a virtual environment operating system is compared to the expected behavior for the virtual environment operating system at step 725. For example, the expected behavior may involve a particular process changing an operating system parameter value, when the actual behavior may attempt to change the operating system parameter value without using the particular process. The actual behavior may involve an attempt to change the settings by code executed by an application. If any difference is detected between the actual behavior and the expected behavior for the virtual environment operating system, the suspicious network data associated with the actual behavior is identified and processed as malicious network content at step 735 and the method of FIG. 7 continues to step 740. If no difference is detected, the method of FIG. 7 continues to step 740.

The actual behavior is compared with expected behavior for a virtual environment network at step 740. If any difference is detected between the actual behavior and the expected behavior, the network data associated with the behavior is identified and processed as malicious network content and the process of FIG. 7 then ends. If no difference is detected, the suspicious network data is not identified as malicious network content.

In some embodiments, scheduler 140 can detect malicious content from the behavior of a virtual environment application, virtual environment operating system, or virtual environment network “on the fly” or instantly during replay of the suspicious content in the virtual environment rather than waiting until suspicious content replay has been completed. As suspicious content is replayed, scheduler 140 may compare each incremental behavior of a virtual environment application, operating system, or network to the corresponding next expected incremental behavior. If the next actual incremental behavior does not match the next expected incremental behavior, the suspicious content responsible for the actual behavior is immediately identified as malicious network content and the malicious network content is processed. By comparing the expected behavior and actual behavior during replay rather than after replay has completed, malicious network content can be identified during the replay of the suspicious content (i.e., “on the fly”) and subsequent occurrences of the malicious network content can be detected more quickly.

FIG. 8 is a flow chart of an exemplary method for identifying and processing malicious network content. In some embodiments, the method of FIG. 8 provides more detail for step 435 of the method of FIG. 4. First, an identifier is created for malicious network content at step 805. The identifier may be generated at least in part based on information within the malicious network data.

Network content data associated with malicious network content is then collected at step 810. The collected network content data associated with the malicious network content may include the data packets that include the identified malicious network content, code retrieved by the malicious network content, source information that provided the malicious network content, and other data.

After collecting network content data, a heuristic is generated to identify the subsequent malicious network content associated with the malicious content data at step 815. The heuristic is generated such that it may identify network data copied and provided by network tap 115. In some embodiments, the heuristic is a signature of the network content data. In some embodiments, the signature can include or be derived from data packets comprising the malicious network data, an identification of the application that processed the malicious data, a byte sequence of the malicious data, and other data that is capable of identifying the malicious network data within a stream of network data received over a network.

The generated heuristic is then provided to heuristic module 130 within system 125 at step 820. Once provided to heuristic module 130, the heuristic module 130 may apply the heuristic to network data retrieved by network tap 115 and provided to malicious network content detection system 125.

In some embodiments, a signature may be generated immediately upon detecting the malicious network content, such that the signature can be applied to subsequent network content with minimal delay. Generating and applying the signature immediately against subsequent network content enables the present system to provide real-time detection and protection against malicious network content. For example, if a virtual environment agent 330 detects that network content improperly changes a virtual environment operating system setting, the agent, scheduler, or heuristic module (or a combination of these) may generate a signature for the corresponding network content. The heuristic module may then apply the signature to subsequent network traffic copied by network tap 115. If any network content in subsequent network traffic matches the signature, the subsequent network traffic can be blocked or otherwise contained without affecting client 110.

In addition to providing heuristics against subsequent or future malicious network content, measures may be taken to remove the malicious network content from computing systems which have already been infected by the content. Script code is created for disinfecting live environment components at step 825. The script code is generated for the purpose of restoring a real environment component from damage caused by the malicious network content. The created script code is then distributed and executed among computers suspected of receiving the malicious network content at step 830.

Identifying and processing malicious network content is further discussed in U.S. patent application Ser. No. 12/263,971, filed on Nov. 3, 2008, entitled, “Systems and Methods for Detecting Malicious Network Content”, which is incorporated by reference herein in its entirety.

FIG. 9 is a block diagram of an exemplary malicious network content detection device. In some embodiments, the method of FIG. 9 provides more detail for system 125 in FIG. 1. The malicious network content detection system comprises at least one or more processors 905, memory system 910, and storage system 915, each of which can be coupled to a data bus 920. In some embodiments, data bus 920 may be implemented as one or more data buses. The malicious network content detection system may also comprise a communication network interface 925, an input/output (I/O) interface 930, and a display interface 935. The communication network interface 925 may couple with the network 120 via a communication medium 940. In some embodiments, the malicious network content detection system may couple to a network tap, such as the network tap 115, which in turn couples with the communication network 120. The bus 920 provides communications between the communications network interface 925, the processor 905, the memory system 910, the storage system 915, the I/O interface 930, and the display interface 935.

The communications network interface 925 may communicate with other digital devices (not shown) via the communications medium 540. The processor 905 executes instructions which may be stored on a processor readable storage medium. The memory system 910 may store data permanently or temporarily. Some examples of the memory system 910 include RAM and ROM. The storage system 915 also permanently or temporarily stores data. Some examples of the storage system 915 are hard disks and disk drives. The I/O interface 930 may include any device that can receive input and provide output to a user. The I/O interface 930 may include, but is not limited to, a keyboard, a mouse, a touch screen, a keypad, a biosensor, a compact disc (CD) drive, a digital versatile disc (DVD) drive, optical disk drive, or a floppy disk drive. The display interface 935 may include an interface configured to support a display, monitor, or screen. In some embodiments, the malicious network content detection system comprises a graphical user interface to be displayed to a user over a monitor in order to allow the user to control the malicious network content detection system.

The foregoing detailed description of the technology herein has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the technology to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the technology and its practical application to thereby enable others skilled in the art to best utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the technology be defined by the claims appended hereto. 

1. A method for detecting malicious network content by a network content processing system, comprising: receiving network content detected to be suspicious; configuring a virtual environment component within a virtual environment to mimic a real application configured to process the suspicious network content, the virtual environment configured within the network content processing system; processing the suspicious network content using the virtual environment component within the virtual environment; and identifying the suspicious network content as malicious network content based on a behavior of the virtual environment component.
 2. The method of claim 1, wherein the suspicious network content includes one or more data packets associated with a suspicious characteristic.
 3. The method of claim 2, the one or more data packets comprising a copy of an original group of one or more data packets configured to be processed at least in part by the real application executing within a real environment.
 4. The method of claim 1, wherein the network content is a copy of network content processed by a real application.
 5. The method of claim 1, wherein the virtual environment component is a browser application.
 6. The method of claim 5, wherein the virtual environment browser application renders the suspicious network content as at least part of a content page.
 7. The method of claim 1, wherein the virtual environment component is a virtual operating system.
 8. The method of claim 7, further comprising monitoring changes to the virtual environment operating system by an agent, the suspicious network content identified as malicious network content based on detected improper changes to the virtual environment operating system.
 9. The method of claim 1, wherein processing the suspicious network content includes determining an observed behavior of the virtual environment component differs from an expected behavior of the virtual environment component.
 10. The method of claim 9, wherein the observed behavior includes one or more actions performed by executable code contained within the suspicious network content.
 11. The method of claim 1, further comprising: generating a signature to identify network content that matches the malicious network content; and applying the signature to subsequently received network content.
 12. A computer implemented method for processing network content, comprising: receiving suspicious network content, the suspicious network content detected within a copy of network content communicated over a network; configuring an agent to monitor processing of the suspicious network content within a virtual environment; configuring at least one virtual environment component to process the suspicious network content within the virtual environment; detecting an anomaly associated with the virtual environment component using the agent; and generating a signature from the suspicious network content to apply to subsequent network content.
 13. The computer implemented method of claim 12, wherein the agent is further configured to monitor changes to a virtual environment operating system within the virtual embodiment.
 14. The computer implemented method of claim 12, wherein the agent is further configured to initiate generation of the signature based on detecting the anomaly.
 15. The computer implemented method of claim 12, wherein the agent is further configured to monitor behavior of a virtual environment application within the virtual embodiment.
 16. The computer implemented method of claim 15, wherein the virtual environment application is configured to mimic a real application which sends and receives data over a network.
 17. The computer implemented method of claim 15, wherein the virtual environment application is configured to mimic a browser application.
 18. The computer implemented method of claim 15, wherein the virtual environment browser application is configured with a proxy address, wherein the agent is further configured to detect whether code within the suspicious network content and executed by the virtual environment browser application attempts to transmit data over a network without the proxy address.
 19. A computer readable storage medium having stored thereon instructions executable by a processor for performing a method for detecting malicious network content, the method comprising: receiving suspicious network content; configuring a virtual environment component within a virtual environment to mimic a real application configured to process the suspicious network content, the virtual environment configured within the network content processing system; processing the suspicious network content by the virtual environment component within a virtual environment; and identifying the suspicious network content as malicious network content based on a behavior for the virtual environment component.
 20. The computer readable storage medium of claim 19, wherein the suspicious network content includes one or more data packets associated with a suspicious characteristic.
 21. The computer readable storage medium of claim 19, wherein the virtual environment component is a browser application.
 22. The computer readable storage medium of claim 19, wherein the method further comprises an agent that monitors changes to a virtual environment operating system, the suspicious network content identified as malicious network content based on detected improper changes to the virtual environment operating system.
 23. The computer readable storage medium of claim 19, wherein processing the suspicious network content includes determining an observed behavior of the virtual environment component differs from an expected behavior of the virtual environment component.
 24. The computer readable storage medium of claim 19, wherein the method further comprises: generating a signature to identify network content that matches the suspicious network content; and applying the signature to subsequently received network content.
 25. A system for detecting malicious network content comprising: a first module that accesses suspicious network content; a pool of virtual environment components; a scheduler that retrieves a virtual environment component from the virtual environment pool, the virtual environment component configured to mimic a real application; a replayer that processes the suspicious network content using the retrieved virtual environment component within a virtual environment.
 26. The system of claim 25, further comprising an agent configured to detect changes to a virtual environment component within the virtual environment.
 27. The system of claim 26, wherein the agent detects changes to a virtual environment operating system.
 28. The system of claim 25, wherein the scheduler retrieves a virtual environment browser application.
 29. The system of claim 25, wherein the scheduler retrieves a virtual environment operating system
 30. The system of claim 25, further comprising heuristics logic that generates a signature based on the suspicious network content and applies the signature to subsequent network content. 